Apparatus and method for making a stitch-bonded fabric

ABSTRACT

Method and apparatus for the production of a stitch-bonded fabric in which the stitches are locked by the formation of tufts or loops of fiber which are interlocked into the stitches of thread produced by the reciprocation of a series of tubular or slide needles. The invention also provides timing of the movements of the slide or tubular needles relative to the movements of the closing wires or rods for these needles and to the control of the distance moved by the needles and the closing wires or rods so that the wires or rods do not penetrate the fibrous batt completely and the degree of penetration of the needles is controlled to prevent the creation of voids in the batt which will prevent the formation of fiber loops when the needles are retracted to form stitches.

United States Patent Wildeman 1 Mar. 7, 1972 [72] lnventorz Arno EdgarWildeman, Bowdon, England [73] Assignee: Cosmopolitan Textile CompanyLimited,

Chester, England [22] Filed: Oct. 17,1969

[21] Appl.No.: 867,331

FOREIGN PATENTS OR APPLICATIONS 268,231 6/1966 Australia ..66/85A1,495,184 8/1967 France ..66/85A Primary ExaminerRobert R. MackeyAnorney-James E. Nilles [57] ABSTRACT Method and apparatus for theproduction of a stitch-bonded fabric in which the stitches are locked bythe formation of tufts or loops of fiber which are interlocked into thestitches of thread produced by the reciprocation of a series of tubularor slide needles. The invention also provides timing of the movements ofthe slide or tubular needles relative to the movements of the closingwires or rods for these needles and to the control of the distance movedby the needles and the closing wires or rods so that the wires or rodsdo not penetrate the fibrous batt completely and the degree ofpenetration of the needles is controlled to prevent the creation ofvoids in the batt which will prevent the formation of fiber loops whenthe needles are retracted to form stitches.

4 Claims, 7 Drawing Figures PATENTED R 7 i972 SHEET 2 [1F 4 PATENTEUMARH912 3 646,780

SHEET 3 [IF 4 INVENTOR: A E. W/LDf/Wfi N APPARATUS AND METHOD FOR MAKINGA STITCH- BONDED FABRIC BACKGROUND OF THE INVENTION This inventionconcerns nonwoven fabrics and in particular a nonwoven fabric in whichlines of stitches are provided to assist in the consolidation andreinforcement of a nonwoven web or fleece. Such fabrics have recentlybecome known as stitch-bonded fabrics which term will be used in thisspecification to describe the fabric to which reference is made.

Basically a stitch-bonded fabric is produced by the provision, in afleece lap, of a multitude of longitudinal rows of seams. This type offabric has the disadvantage that the seams, which are produced by theuse of, for example, a series of slide or tubular needles, are capableof being easily pulled out from one end or from a break in the stitchingyarn, since the stitch formation of each row consists essentially of aseries of interengaged loops.

According to the present invention there is provided a stitch-bondedfabric in which the stitches of each longitudinal row of seams arelocked against removal by causing fibers anchored in the fleece tobecome interengaged with the stitch loops.

The invention will now be described further by way of example, withreference to the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a part sectional view of thestitch forming mechanisms of a machine made in accordance with theinvention;

FIGS. 2 to 5 are sectional views of part of the stitch-forming mechanismof the machine of FIG. 1 showing one stitch-forming cycle of themachine;

FIG. 6 is an enlarged, somewhat schematic part sectional view of part ofa needle showing the effects of various degrees DESCRIPTION OF APREFERRED EMBODIMENT In the following description no reference will bemade to the formation of the fleece since this can be produced in anyone of a series of well-known methods.

To produce a stitch-bonded fabric in accordance with the invention afleece 10 is passed through a knitting machine which incorporates a rowof slide needles 11 (that is needles having on one edge a groove 12 inwhich a wire rod 13 can slide to open and close a hook formation 14 atthe needle point). Alternatively tubular needles may be used in which awire rod slides in or through a hole in the needle to close the hookformation, which would be a minor variation.

The slide needles 11 are mounted upon a carrier bar 15 which isreciprocable towards and away from the fleece 10 to cause penetrationand retraction of the needles through the fleece.

Mounted above the carrier bar 15 and adapted to carry the wire rods 13is a rod mounting rail 16 which is also reciprocable towards and awayfrom the fleece 10. The reciprocation of the mounting rail is controlledindependently of but in timed relationship with the carrier bar.

It is important to note that the uppermost face 14a of the hookformation 14 lies in the same plane as the lowermost point of the groove12 of the needle 11 so that, when required in the cycle of operations(to be described below) the rods 13 can overlie the hook formations 14to close the hook.

Mounted forwardly (relative to the fleece 10) of the carrier bar 15 andin fixed condition is a holding member 17. The holding member 17 isconveniently secured to a part 18 of the machine frame. Projectingupwardly from the holding member 17 and spaced to allow passage of theneedles ll therebetween is a series of fleece guide arms 19 the freeends of which are connected to a tie bar 20, which extends across theworking width of the machine. The tie bar 20, arms 19 and the front face17:: of the holding member 17 to serve collectively as afleece andfabric guide against which the rear face" of the fleece and thejust-formed fabric passes when the machine is in operation. In additionto guiding the fleece and fabric, the fleece and fabric guide serves toretain the fleece and fabric against movement with the needles duringtheir retraction from the fleece.

Spaced from the arms 19 are a series of support pins 21, there being asupport pin in alignment with each arm 19. The support pins 21 arecarried at their lower ends in a groove 22 formed by a front supportrail 23 and a cloth retention bay 24 with a step 24a on its leading edgedefining a restricted throat for the fleece. The two elements 23, 24 aresecured together by studs or the like (not shown). Alternatively, aunitary grooved rail may be provided to replace the elements 23. 24, thepins being seated in the groove. At a position below the needles 11 thetwo bars are angled away from the front face 17a of the holding member17. The pins 21 at their upper ends are mounted in a beam 25 whichextends across the working width of the machine. The beam 25 and pins 21collectively form a fleece guide and that part of the cloth retentionbar 24 which lies parallel to the face 17a of the holding member 17forms a cloth guide for the front face of the cloth. It will beappreciated that, by virtue of the construction and disposition of theelements 20, 19 and 17 relative to the elements 25, 21 and 24 the fleeceand cloth is, as it is moved in the direction of arrow F, constrainedbetween the fleece guides and the cloth retention bar 24.

Spaced from the front bar 23 at the side remote from the needles 11 andat the level of the needles are a series of thread guides 26 each havingan eye 27 through which the threads pass. There is of course a threadguide 26 for each needle 11. The thread guides 26 are carried by a rail28. Threads 29 are passed through the eye 27 of each thread guide 26.The rail 28 and thus the thread guides 26 are adapted to reciprocatetransversely of the machine with a slight rise and fall so that a thread29 can be laid in the hook of each needle I 1.

A cycle of operations will now be described with reference to FIGS. 2 to5 which show the formation of a first stitch in a fleece. The threads 29are held at their free ends 29a and with the needles 11 at their extremeforward position (in which they have completely penetrated the fleece llarid in which the hook ends 14 lie in front of the guide pins 21) thethreads 29 are laid in the hooks of the pins 11. In this position of theneedles 11 the wires 13 have their extreme ends adjacent the guideneedles 21 but within the fleece thickness. As can be seen from FIGS. 2to 5 in particular the fleece is retained by the pins 21 againstmovement with the needles 11 during their insertion into the fleece.

The initial movement of the needles 11 is rearwardly in the direction ofarrow N to cause the needle hooks 14 to be retracted into the fleece insuch manner that before the hook end of each needle 11 is closed by arod 13 a bunch 30 of fibers of the fleece are entrained by the needlehooks 14 (see FIG. 3), which fibers lie in the path of the hooks 14 byreasons of the inherent resiliency of the fleece. This is aided by thecompression applied to the fleece at step 24a of the cloth retention bar24 below the needles 1!.

As the needles 11 continue their rearward movement the rods 13 close thehook ends 14 and when this has occurred the rods 13 are retracted in thedirection of arrow R in unison with the needles until the needles I1 androds 13 are located rearwardly of the arms 19. At this point in thecycle a loop 31 of thread 29 has been formed through the fleece andadditionally a loop of fibers (formed by the bunch 30) has also beenformed by fibers drawn effectively from the front face of the fleece(See FIG. 4).

At this point in the cycle, the fleece with its loop of thread is movedin the direction of the arrow F, that is in the take up direction. Whenthe requisite movement is completed the needles 11 are moved forwardlyand the rods 13 remain stationaryv The forward movement of the needlesin the direction of arrow N opens the needle hook 14 thus enabling theloops 31 of yarn 29 and the looped bunch of fibers 30 to be pushed ontothe shank of the needles 11 by the resistance to forward movement of theyarn and the fiber loop by the fabric. The rods 13 now commence theirforward movement in the direction of arrow R (See FIG. 5), whichmovement continues until the tips of the rods 13 reach the positionshown in FIGS. 2 and 5. The needles 11 continue their forward movementuntil they reach the position shown in FIGS. 2 and 5 at which time thethread guides are reciprocated to lay the threads 29 across the needlehooks 14. The cycle is then repeated and as the needles 11 and rods 13are approaching the limit of their rearward motion in unison, the newloops of thread 31 and the new bunches of fibers 30 are drawn throughthe previously formed loops to form a new loop stitch.

Reference to FIG. 6 shows that the number of fibers used to form theloop 30 depends upon the number of fibers contained within a triangulararea bounded by that part of the bottom edge 13a of the rod 13 whichprojects slightly from the end of the groove 12, the outside face of thefleece l0 and the angular face 14b of the needle hook 14. In FIG. 6 theline 10a representing the outside face of the fleece is shown in oneposition relative to the tip of the rod 13 and the lines F and F showrespectively the effect on the triangular area of causing the needle toextend to a greater or lesser extent beyond the face of the fleece.

As can be seen if the needle is made to penetrate through the fleece toa relatively large extent the area of the triangle will be small and fewfibers will be available to form a loop 30. On the other hand ifpenetration of the needle is to a lesser degree there will be a greaternumber of fibers available to form the loop 30. The degree ofpenetration of the needles is adjustable and thus the requirements ofmanufacturers of stitch-bonded fabric can be met. It should beappreciated that the through penetration of the needle hook must not beso great as to result in the tip of the rod 13 extending beyond the faceof the fleece nor in fact so great as to cause the needle to havepenetrated to an extent such that a void will be created in the fibersof the fleece. Such a void would be created if the needle were caused topenetrate to such an extent that the whole of the angular face 14b wereto extend beyond the face of the fleece since the fibers of the fleecewould be opened to the full height H of the needle and as shown in FIG.7 upon retraction of the needle in the direction of arrow N the hook endwould enter the void V which, due to the difference in height H betweenthe needle shank and the height H at the tip of the hook end, wouldresult in no fibers being collected by the needle hook.

It is found that, due to the formation of fiber loops in conjunctionwith thread loops, the threads cannot now be withdrawn from either endor from a break due to the locking action of the loops of fibers andthus the disadvantage of the prior art stitch bonded fabrics is overcomein a simple and effective manner which does not require the provision ofany more yarn than was previously required.

The size of the stitches can be varied as can the spacing between therows of stitches.

lclaim:

l. The method of producing a stitch-bonded fabric having fleece andfibers, said method including the steps of reciprocating a series ofneedles through a fleece, while progressing the fleece successivelybetween each successive needle insertion,.halting a rod or wireassociated with each needle within the fleece, halting the needles afterpenetration of the fleece and before they have penetrated to an extentsuch that the greatest height of needle has passed through the fleece,laying a thread over the hook of each needle, retracting the needles todraw the threads through the fleece in the form of loops, andsimultaneously to collect by the inherent resiliency of the fleece abundle of fibers from the region of the face of the fleece from whichthe needle hooks have projected, closing the hooks of the needles by thewires or rods to retain the threads and the fiber bunches in the needlehooks,

retracting the needles together with said collected fibers and thread insaid hooks, opening the needle hooks after retraction of the needlesfrom the fleece, moving the needles into the fleece after progressingthe latter in the take up direction thus to cause the threads and thefibers to lie on the shanks of the needles, halting the wires or rodswithin the fleece and projecting the needles through the fleece, layingfurther loops of thread on the needles and repeating the cyclecontinuously to produce lines of fiber-locked interengaged stitches ofthread to produce a fabric.

2. The method set forth in claim 1 including the step of halting theretraction of said needles outside said fleece, and also retracting saidwires to open the hooks of said needles, and when said needles againcommence forward movement, the loops of thread and fibers from the hooksare transferred to the shanks of said needles for interengagement withsubsequent loops of thread and fiber.

3. Apparatus for producing a stitch-bonded fabric having a plurality oflongitudinal rows of stitched seams and in which the stitches are lockedagainst removal by causing fibers anchored in the fleece to becomeinterengaged with the loops of the stitches, said apparatus comprising aseries of needles arranged to penetrate a fleece, hooks on said needles,said hooks having an inclined surface, a hook-closing wire for eachneedle, thread guides for laying threads across the hooks of saidneedles, means for moving said needles collectively to reciprocate suchas to penetrate through and retract from said fleece, independent meanscollectively to reciprocate said hook-closing wires in synchronism withsaid needles and to limit the stroke of said wires to cause entry intobut not penetration through said fleece and not sufficiently to coversaid inclined surface, and to retract said wires, whereby said hook endsof said needles may be provided with threads from said thread guidesand, upon retraction may collect in said hook a loop of fibers from saidfleece to draw same together with said yarn through said fleece andcause interengagement of loops of thread and interlocking of said loopswith loops of fibers, and a cloth retention bar below said needlesdefining a restricted throat for the fleece.

4. Apparatus as set forth in claim 3 including, spaced fleece guidesbetween which said fleece may pass, spaced members on said fleece guidesbetween which said needles and said wires may reciprocate, and fabricguides associated with said fleece guides and below said spaced membersof said fleece guides between which a fabric formed by the production ofstitches therein may pass, said fleece guides and said fabric guidescollectively constraining said fleece and said fabric from movement withsaid needles during insertion and retraction thus to enable correctformation and tightening of stitches of thread and loops of fiber to beachieved.

1. The method of producing a stitch-bonded fabric having fleece andfibers, said method including the steps of reciprocating a series ofneedles through a fleece, while progressing the fleece successivelybetween each successive needle insertion, halting a rod or wireassociated with each needle within the fleece, halting the needles afterpenetration of the fleece and before they have penetrated to an extentsuch that the greatest height of needle has passed through the fleece,laying a thread over the hook of each needle, retracting the needles todraw the threads through the fleece in the form of loops, andsimultaneously to collect by the inherent resiliency of the fleece abundle of fibers from the region of the face of the fleece from whichthe needle hooks have projected, closing the hooks of the needles by thewires or rods to retain the threads and the fiber bunches in the needlehooks, retracting the needles together with said collected fibers andthread in said hooks, opening the needle hooks after retraction of theneedles from the fleece, moving the needles into the fleece afterprogressing the latter in the take up direction thus to cause thethreads and the fibers to lie on the shanks of the needles, halting thewires or rods within the fleece and projecting the needles through thefleece, laying further loops of thread on the needles and repeating thecycle continuously to produce lines of fiber-locked interengagedstitches of thread to produce a fabric.
 2. The method set forth in claim1 including the step of halting the retraction of said needles outsidesaid fleece, and also retracting said wires to open the hooks of saidneedles, and when said needles again commence forward movement, theloops of thread and fibers from the hooks are transferred to the shanksof said needles for interengagement with subsequent loops of thread andfiber.
 3. Apparatus for producing a stitch-bonded fabric having aplurality of longitudinal rows of stitched seams and in which thestitches are locked against removal by causing fibers anchored in thefleece to become interengaged with the loops of the stitches, saidapparatus comprising a series of needles arranged to penetrate a fleece,hooks on said needles, said hooks having an inclined surface, ahook-closing wire for each needle, thread guides for laying threadsacross the hooks of said needles, means for moving said needlescollectively to reciprocate such as to penetrate through and retractfrom said fleece, independent means collectively to reciprocate saidhook-closing wires in synchronism with said needles and to limit thestroke of said wires to cause entry into but not penetration throughsaid fleece and not sufficiently to cover said inclined surface, and toretract said wires, whereby said hook ends of said needles may beprovided with threads from said thread guides and, upon retraction maycollect in said hook a loop of fibers from said fleece to draw sametogether with said yarn through said fleece and cause interengagement ofloops of thread and interlocking of said loops with loops of fibers, anda cloth retention bar below said needles defining a restricted throaTfor the fleece.
 4. Apparatus as set forth in claim 3 including, spacedfleece guides between which said fleece may pass, spaced members on saidfleece guides between which said needles and said wires may reciprocate,and fabric guides associated with said fleece guides and below saidspaced members of said fleece guides between which a fabric formed bythe production of stitches therein may pass, said fleece guides and saidfabric guides collectively constraining said fleece and said fabric frommovement with said needles during insertion and retraction thus toenable correct formation and tightening of stitches of thread and loopsof fiber to be achieved.